SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e36db5f615bb69ad8543ae15e2981c3fd55fed241cce745bb2c65cc2eca96fd' 
  AND token = 'f4lFQGIYbD5NwmFnUNTLS91MZ1LNbReFXtyi7RGtdQA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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