SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e98fcede01c4340cf0bc458033248d1f970f7c9a07bff022526a4bb5ce847c20' 
  AND token = 'fIYYI/hKTj2UuUPYV2ga2nKjS5MdCIKdqdjpz2ZR3iA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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