SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e79697bd28a02d60d399119ceb9fa165fbbf731987e01e4f87b6a52c5609ebea' 
  AND token = 'z5IJGJwx9v/0Yd2WNiF7KUR/Vej1/TFngSqIHFd+9Jg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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