SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '76a96fd4ac867417352ec103137c529302bed10951dfd04530246bfd91ad8cd5' 
  AND token = 'GoSKfcY8MVgk/ZBmgDUKdQUOBoc/58zkQvvcUBu/L48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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