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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6420fdd39cf90920463efdd160bb4b2d9a8787d118c031a67e07b12c854ef46f' 
  AND token = 'uNMLaOWkAwUe5Vu6xZ82Z2cjEx0W3OcMQFnpnfIvmoI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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