SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd88f8ba467454796433be066f1a8ffb4473e440030a5deee26604106879d56dc' 
  AND token = 'F7C2/WwtJ1QxEfEGnVZ9UwcWPKqCpngtrSTICbUD9Cw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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