SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '63c85b3f028c2d942af9d923f91e0c659e321d71a4c73759e6f5c6484b4b8b3f' 
  AND token = 'T/rzsW4ZLGPWZMnNkTKSD7SxdLEHid3HhQNnU9RcgeY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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