SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ccafbf3bdff845999e0e98502f4c4f796625c95330436829e6c461499947ef3' 
  AND token = 'qS4StzI68hFteyyVKo+aK/fWVGJ3S2UukKbckR0Qjcg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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