SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2910de2b2b7343af77517cfaab8317b986b08eab4694531781a40779f12d0477' 
  AND token = 'RHrfxf4JwtwJOufj69IolfnZNhOfaxFlEzczAxdxs3Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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