SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a83f163b570946d8c5935a0f51ccd52ebef64069f13a0bff374740cb6b70ee97' 
  AND token = 'HBtDX8DTkLpwRX75xJsgcbtkE0CBZQTkeoMA85obf3k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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