SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec6d45745fed57e754b4734090dfa79b14ba68cde1718d35c86d841127adcb94' 
  AND token = 'PTwYvIBpMFRY9I0Ox/3fKfYQUzcNH85EpNi90aFwIOU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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