SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bef788b42885441cf5bc8526b97033907a9de7ccf657dc9f5b690b4449d746cb' 
  AND token = 'myPnpyHd+fk4LjVTwBYRsx6PH2k+1AjhgjZxaKHxXlk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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