SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71adabdd0c76a7e63c0a6d7b72ae6a2580cafb578d610d95bae0df90fdea3604' 
  AND token = 'WfkY2JZfZ/is5s3j6vvHbDtsLmvVj4ueYiATSAXjw6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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