SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86df756959a9ab9015c6a3764179908cfbf0d33dc7ca8e6f0cd2608bb5dc2564' 
  AND token = '7+xCYXzpwz5Nuq6+XAHYtXuBJoHAI0qPbpj9rSjkQAw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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