SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cf1c9004c3e8857c171f4298cf125766bf34bc738ae0a271b494d0d91738598' 
  AND token = 'wj3CFEJBTTBb2LwvOYTAGeKE+MBQQNs/SH+dIG8DW6M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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