SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '9b5cbf430e20bd4d67f0f7f3d3fda0316503c8e54131c38fc9df615b5b5ad223' 
  AND token = 'skw7yrnKBZpW8iJP0MuniydPqTbLoAgID+6+eAzrIP4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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