SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3b67110cf8e81a21b8397de1b8c9358b57365a6d76d8c1fcbe95e81935652ed' 
  AND token = 'jQKEGDzg0ll8gfwp3mRcgqHMM+2BMjhCCXLrPOwz5T8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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