SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '427faf107198fcdcb651aab84d4f4560e282a678596c1ff33c590dda6c6e3de7' 
  AND token = 'RrwjtC+7AtklX5VURqkQCNGRvN537ZSnBA7EXGYufyo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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