SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ddbe0576bd35bdafcae969a129dc0250d781f29c9996188a2c32f83836d1e017' 
  AND token = 'TpdXD5kMduT+hHrpNCqRwnfFJR4ztSxYK57fbxFFfAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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