SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5030f9cc30e4eaeb15835922403dd0a49915996be808226ab293c27efd77363e' 
  AND token = 'R52Njen4ftmVtURWqaOZipTQxrrLowEhvFCkLK7AocM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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