SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3a41692ae70c3edb8036c97747640999c0af1568f3c8e9290095572cc3c9d6a9' 
  AND token = 'mPyAT+AVfC+FEST6TVtJmKev6Snj4VYM04SYHgzj7/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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