SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8da3fbe98e9eb36a6035473ad00fdd0e303a7805c80c397a3fa661b287561567' 
  AND token = '5aM76kYcPj/4+XjRdkeTxgxAHNvggoTwlRU7k3Vyb8k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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