SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd88d7748a48d0bcbc84e36e0fe812337cc7dd8d8be2f6bc37fe365dab2c2279f' 
  AND token = '5Lw7yD5cSj5Y/2h9omntwEBy2utN6+PGH1lPNjhtgOA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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