SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6ddda354ffcd3a6ae13a2b0f3429c700417a338620f7606d47915a9049f42cb' 
  AND token = 'tdGKewEK0YRN+B2eKAzCto51o2Ktf1A2zyZhRfsOcBI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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