SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e767e75319693c6090f9859f5c157f4c04199f4bc83cb590b61f06885fd9889' 
  AND token = 'djsFOFEEil/k6ZBvufYJG5WvPZCpwPJU2DzXKXt9Q+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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