SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c4fbac3782cf937758b1387644e83a2dcec17109e29d0e46bd19287e14bab98' 
  AND token = 'CbuXJfBNmUnywRmJR2S4ajSr5zQLtdCQeNp/DirDx2s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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