SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6516b24f083f6b447384a90ad3762a412f2591efc77581053142c29f76774c7e' 
  AND token = 'Bh71p6CbKXp1gCu4okxvnTk0c2ZuKVOkQO1+tfI1eU0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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