SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '69717f37f9cb3ca75f1059aab544955cdde4bc2d9f82514964afa8bb66bdbf41' 
  AND token = 'rS662X/uZjPpjqzpjwv87Zv/LaB/wN+U9nooY56dLlc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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