SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1db602a65fec117660f4832cf0747a8cd29641a90f2b3a758d1cab206599709d' 
  AND token = 'C63U1wv9n8sa8TXZiVZdu3km1IBPkdHXIJYHqMzD/7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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