SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5a76b226f4784b41f01854f61e951a6a7098703a8d425e8429855d985e6422f2' 
  AND token = 'gj+GtyMJGDoFnBB2XuJ3LSL58dp6Z4n/X3wasisqZtM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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