SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '01d533b48ba49903dafcb6852e3367df1bf9df776110db5853b9feb1f6d99d81' 
  AND token = '9FzisfL09ssyXnt9FITsLTEOBGQjXEIWChmuIBXuESs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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