SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '0546c3f1319f4cb86ac7cb58f36688e8062789d5f16548e0c12b9f3008c5c491' 
  AND token = 'EJDTmcBTgU/mTjeJMT1z0FidrH8HleFDkkcRSZqV3kI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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