SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18955c3eedcb269697a06047fa65623e94095cfa30c39a44c45b301b8a893125' 
  AND token = 'tV3N+VfimKUmmKZ56WW0jhCLl5g+69q8J3PQHIHvzkI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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