SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aeb569adea553abb5fd27864f717c5829388f0d3b5bb46c938be2bd57d26933f' 
  AND token = 'tUIreqWTk9+JY9/oyob/JK1w0HMrTqzrSliwwkghqS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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