SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7856c8935873ffee3c83e753a685d58e0e27012a11c22cf0e2381062b1c47a8c' 
  AND token = 'HmwbmqaPhrnZhkAiEeUHov51/9SImAH3hboIrFzQwGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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