SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f99f0fc438f6208535cf04443e3565666c6890c1923e6a421c1fe28f7713e978' 
  AND token = 'Q0nmDloa0QTD9Cfbbgo62YG+ezughZX/33gXzM4dMdM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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