SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a84c4498cf08027b97e997f2acfbe762065b2fa46b3fc9ed9f2e5f16cb65e6c8' 
  AND token = 'CssrZ7sbQ/E0UuMHLmRvF15aHsDxqsALCqcit/yL+fU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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