SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f462f173f8de89567bd688902b570c5d78dfc58b05d023382d5039db9743ae2' 
  AND token = 'X/ZiHtq9muj1Ed5zDl+YGAQqQoNf0RvoQgLD7dsqQ+s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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