SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8acbb61c936f754fb81de0df217d33849ee650d7a74fde4f8b41ee6aa2a44e1' 
  AND token = 'MMO60hSkqmjXo4NdkrWJrdH1/Gv6XFwQ2FXGpIYPbVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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