SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a8e6db79613d66af9150ae6a2d826113a3a684d6c9f435abca7d29dcbc1bdd1c' 
  AND token = 'vSIFBspKLk/T5ZqLDN8KEmwjqALVlktyeLOu6pA6CrI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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