SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '688be2ab45cd6116202bdc304a0995601b328140d7ed03ed6b286ebb6347cc13' 
  AND token = 'BS+e4jqNxtYZTBTOZGuMHgsOIp6G+HiwRNRV6k8OXO4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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