SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5974051b6f3cafdb740c33f50e687b4380a12636a149f15efed379f91698d826' 
  AND token = 'xtWgKxFqHNOZQMlSHomvDTBlxU5TQIKuZhejFprn0T0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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