SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e8ff7c2a4abb3700b6f3ebd6ef5367b12852596a0e28f6e65155abf2b5d08ff' 
  AND token = 'T6WuZnb6sKQzitkwBtYSlgwWG8VTSOgYmx5Xo9X9rfE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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