SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88d7253c0498925ed0456923995c45b3391bfc184ccb3976c43452f1129aaffd' 
  AND token = '3Y2VHsqYo1dbwr+qoHYWbpy2CK7RJc4ztJeVw4PfGpE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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