SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61403d586b7e2b22b7b4461e9ffc39bb510d454b5b899925fb6b5a60735897c5' 
  AND token = '5YCH/Gy/p+h4OxKsWv7+Etp6j5ALtG8LoyR7Kq3ZwiA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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