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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c9f1891488aa9c90f5f82833cfb13aba78d4452bde14512b7ff1b0d28adb1a5' 
  AND token = 'hR4ozFFiiQ9EI5cRjDzEcWawYhxKVSxoyLc5SeEgeCs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}