SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c58e7872c7478150493a09c07ee87ba0358de0999f3a48cac0db69857402fd72' 
  AND token = 'OTUdWiPIvCbLSL/Db3hQ5GC/AoOQQbCcuOsSdqYrw+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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