SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a53884f9bea8e91df5304a3307d24e51dbc8a679cfd5894020c4c851a8abea25' 
  AND token = '5xEwpxdbRSVbWC0Uae84PTAL6z7hOm5YVESinBBRASg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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