SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '91c21d4587a203446bdc8643b415dbed579683329460b787a5f9fdc251a26df9' 
  AND token = 'Zlt+gQ2ZwkHEX6G9NuX+aF557PfJxi2CELT7VGREcoQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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