SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd71391c3df3cf0db75f9a383056ebeeaf692086ff2f4cea92b688a861451c3c9' 
  AND token = 'blx5onw4m/3uIspZZL0sSqRoQxRGxydaZX52BR03CoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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