SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf9e803598e345e0a7fe38e9952fd31e750e7c672efcba81f1cdb5cb705b4082' 
  AND token = 'fpOMPrWNlDIgsrMrbYJEI3EAiVz8fpL0ima15UFOILo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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