SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a95a4e6c998000c5ca462f4d596dc88cc83ebd36217554749eb65b20e306d343' 
  AND token = 'gzni0RjuW29D7lm1w/fKQOccLZHy/TfgE2kGu01/vhY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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