SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49a4127623a99d588368da5a4637185f9936d092419eb54cb61e3b13a85e3fab' 
  AND token = 'jJ47Wf2/xDRom3nA3KxkgIUy/AqegBihvu8jyz4t0Ks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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