SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '397a49efc984cf3f88908be1babf709414296f6d1fc30fdac0d9e45864ff427d' 
  AND token = 'yHipv3yImqNvn80MJqNzh8AJzG1/unMsWBKJXl6sGPs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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