SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba4f0d1756a7527b46211230584696518375e27e42c76faa36c4f6865ce5236a' 
  AND token = 'DwygWqBmzHtviPh4gtLv7+Znx9OlswJYpRPi5YJzmBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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