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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92c6ce7c38ff6e3b8c1645ab37e2da98a1d1d9361ceada2f64b5a2be209e0ea5' 
  AND token = 'UN9VweOpO6j2PP0xjH/4hhBa7gAqgFA+pQPKxsuoaW0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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