SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94b4902bcb8e51642c39f555318dbd5f9df35888eabb3d9fe737572472b11bfe' 
  AND token = '5KH0QGm5uFdwUgsVNs+2qZYTV6/THMsC8Zhyj+r4AJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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