SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6388309025ace3117766c28e96ba0c9e839d35580251f13ffa6c0db66f9e751c' 
  AND token = '4pagjaJmB9mDa+U0aWYgE4PKP74wQ7GVhxSXuBwpFMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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