SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2ef7c5f5b148124814a0ebfebca37c604fd2f5c4764161f0293b3f769bc84632' 
  AND token = 'WRg/3wxjYBlqGLXkVDc/QTJJaNs7+9q0knK1coyTG6w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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