SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '950f2a6300d5d042af890750a323568baba5bed9f1bf488934c0eb7e491ff238' 
  AND token = 'yOZlBb2jIvu2ZcOb4JZbOE4fmxx8mA6EuIgcoyMJftU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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