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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '13fb6d3c657c1d3ac2c6ae36f28e81a6df05eab063cba29fdfefb8f356239a19' 
  AND token = 'VrmuPKPUI+CvwSyV9bjW5tHmQgeY/RfMFP6TiAf448c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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