SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72e763233bc90ff61c192bcb291073cb3642017267ede3747c2e1aed63f55264' 
  AND token = 'N3BYEgUwXeHI6ray60BFBteLtBrf0hj60+lzs9o1Q6g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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