SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c62ef551c01dcd1bf63eeeecda34aa9a817876b48cc984a3a742f64b40d24423' 
  AND token = 'Phxuy8iXyemW92CXvyqvU0QgZOzEHfKRy5MsXGRgJFs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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