SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5d1044dd3952bc92750dc9e858eaa95d435e62b6fdc3fcbc437fc7757b48276' 
  AND token = 'jWhThy2+olpFn5/gXvx2FnKiVthPzGIWpevpYWRe16k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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