SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b89af6599563fcd67998764c7da636a1d925bebb135225ca50109de1d24eb996' 
  AND token = 'dbbCn6mHWs+8lFpqmJc2Vm+w5kQsvr6SP9cVKUCjdmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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