SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd446d9589fcf0d532148dea57e614529df01dc8ff2b331d95384471693dbdd76' 
  AND token = 'WA3SbEVitT/XszeVlH8wPGjerj5ZAXQhhdj7fzVpdUc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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