SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9bbb318cd7907b46ca7a748d9b7aa2f70df24af0703b65468a23bcbbf4065b1' 
  AND token = 'AxwTFXCjz7GlVwUcKcw+ogVXFFx3GjBYNRptDiOvHVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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