SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce415ceeea979d9c1305297a6065f7b33a3b38dbbebf134601b8a48abdc621a6' 
  AND token = 'ndmtliGjJgoLeM6p3wqaSaUz1tAxhYZL8EmFiUGwlAc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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