SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2258d389b4ca21324c3fd8b2145bc5495d8d7183dd2b52a94fe7c5a0049e34a2' 
  AND token = 'GXnuWF5fXHiZC5WK6S1fRbCQNF6fNmi/sBfWiWY1l/E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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