SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7f152f9cb5a2384fb95225d2522130d5199b15cb3ed00ca6ac84b763b37055c' 
  AND token = 'w/ZtQxqoAUnEqZvHXTv/ieeXct1MAxIW8hrOD8vFaTU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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