SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0501d8480388683d8e19a448cc492ba30634c73d0d6efa755958286622d49c9' 
  AND token = 'gUV8huR047lqXJyAwXvxqcXigZV5Oxv9Bzr/t4IzY1Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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