SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '101af57562adfd7271583058dc16e959131633618f3fc936242b852af2947ece' 
  AND token = 'QyoYSVMLwdJUyEftanHOjq4ILzKhuZpCS0HHOoM9g1M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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