SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7c33ab41320ceba924283d7235e59ac1c4087b667c12342e0f50012dfa73525' 
  AND token = 'JplDgC+zb7LwM7kIpBZODoMXahyXQzclZ98B+VAULY4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}