SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd2540c083c187dcc97e76c5a18a45232082e3d0032463060b22532d4fd7fc32' 
  AND token = '1AtSqp3dZQOJg5VG8ZuyLImZkZfAlW8SJTN+mFEDZbk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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