SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '463054721e35e108f3c70cf360ddb8c03edca9a215c6aab35d4d2fed87c9a859' 
  AND token = 'SYHQFNZFPce6bH4mJZ3R7xlvCYSQRGt3AAlH+nXXchU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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