SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d3da7e50624b457ca9ab572668eccb07c208cdc51728478d0a1eb03c63f26a7' 
  AND token = 'xFKzGjDRsRMt9XEPldMdPqf6pyauAYl+/T/pnZhhlls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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