SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad3970b5261885a397f7ec78f53b1099d9352254dda7e83e565741cd21d607fe' 
  AND token = 'bzg6uHlHPHC3OmsRmQJZVv4ZoSL8UsOuf7KFyskHjOw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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