SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e56bfdadd22493c52c372d97dde4fd8313183fa92383a4afcca5556e9caab36' 
  AND token = 'B1AarfHYwPwFa7fWpnBGzMqFSNsh0WafJS07VZAWbHk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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