SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5491250d9e61475f48f97128e097bc57bfcfba68c263b65a2f5b8a8ac53ed9b5' 
  AND token = '6kqcFp1EmL+lT4wwIxRduW4bCxVvDJVHQTwxLnhcCYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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