SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2813e1f858f11c04b8e96760d0a7f45997953593f1e565300ac51a5657315902' 
  AND token = 'K51khHYurnSwKP+AbvIJajUFwCRcJoXYiWC2kC47tsY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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