SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d55e6b2d9c350ba32c4f5068e3d3280f009af7cbe85be923302df663ae5d840' 
  AND token = 'ceDHxYSe+huxBX4cF8MfMWO92Nv7RHvLZcdrGZA7uLo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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