SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f738b6866a2bc04c2f80861b25c6b439793cde0ff834236ad342032f9e2f6b19' 
  AND token = '9ZP9UqRxv7efh38FrfbVJ0HN3nXo6czXdFQHygbMWCU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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