SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fb025cbd3aca3d64f6127daa65e13830e239e5df75ba4c7cb6961030a53e787' 
  AND token = 'r72ZvGIvMp56F0pWrlaX0mJlSUwZzbdjbnWT+u1qg8Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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