SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f5b897e6395a4edb3abaff321bcb635d524b587bc6121f7c38626a183a8054e' 
  AND token = 'jXT3xi8ZAg2HEWogia4dFj/Utqw1OAB7xFedhcjGfWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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