SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5429473e55999e59764d7a73d0935f069f16d7925d5cafcabebb974bf3cf49a6' 
  AND token = '/Kwa2fT6AdKnK3O27ajvsnUvyGMaxU9PpO2XreOKeag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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