SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0bb16a8db338bc29432aaaacf1b15bd1adceb752c54fa3bbdf2520b89834fa0' 
  AND token = 'B3ep7iXLZxHIQl9kzk+Ld/9fyxnVAEdcAJbBtVB3fLc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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