SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46dd46988e15506acd6d1aeeb879c662bccc1d27dac403be347871f24f7ff7a9' 
  AND token = 'WlF6Bd5ztxwVfUIwpupLSB6syJRpn5pk2jYbQmh3PmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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