SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9be0056b1a6599a764feee6213a1ba2cca7949660b1984f524c7b2b60d7c84cc' 
  AND token = 'cFJBVLBxZO8M+sDGEiEDs/WD6SqQ0m8fp5cLRU9XLVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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