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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c9ec822b4b842631f2af0f139867e6ba814f5dbf51a7077a9f522cb78f8ee76' 
  AND token = 'k8NzYufQMhWB2ohYSn+lvzMu78wQlyyyOghGv7Nwgz0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}