SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd492e56f7afa788d49e302ca5eea090d58d12f0757224796a461d08fd43d7cc5' 
  AND token = '2wXBilS0PzRfYvkzH5Ta6xaJW9/uXi6WM6J/u3GEnls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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