SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '01cc172bdffb165c9cb7626d4a5b2b670cbdd4635798f4773b514d4a961b8fc4' 
  AND token = 'EMpmPcpUrpqrwGpQZ/+QupwI1pFupFpM//o+VZssljg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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