SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea1dbb315ffb39da4a390d982b0e1fdee30db27d603303a7b6210a12928cc83a' 
  AND token = 'kETKmfKE4gtRxYiP8AFDwKFr7D777H+WUPyr2QTs7NY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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