SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd61bb91a8563b36e5fac29835ee03d9ba24dbe5cf0721f7d0c1e0298bfa941bc' 
  AND token = 'i5o4rTXRxvACtTkRgWxlM35HUd44JvGFMHx3aPfZqv4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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