SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28d0a4ea7179dda75aec5eeb26307d6d812e378ac63287fa09f6d9630d8eecd3' 
  AND token = 'Ciyvexs4pWKb7KmwSkJYIs+wnKtgt/Hs3xRHvB7rRBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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