SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4483f0f2fefde738d987c75605e30fd166a66a1fea789f57fb9b4445b65af138' 
  AND token = 'g1oC7j7pg3+0rlYk678HxOYYyi5vT7Bh1RJzAskw4Vk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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