SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f7704c114c35b3f7537b922240331fa43921b6bcd31f352136966fbf23c2a10' 
  AND token = 'U9QXecszZEEmGqyXRRLmK3qbN3YM5rW5OlsoanrbVpc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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