SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c924d501b903f4e7d8905988d60c5492ea748e1193839119996fa983295e8324' 
  AND token = 'DprmyDy1u8bm0dbS+YjXktOUL/uP/nCVbkse1xERpxs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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