SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e46c4ff535e5579020dc86ba7b9d860f9f12296e58ce3431ae35d6af97c5305d' 
  AND token = 'nlYzdYLmrab8LhRrbaAYZlFgqy+iXw5fK7JWCAMSFeU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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