SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82b8e0a18040ac662c9fdcfc0fd977ee5d030ad3dcd036b384464bc2e5b144ce' 
  AND token = 'i10e6sPluKNESbkrii7rPxCZsYMIU/9RS/OBGcEQx4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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