SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c95a395db714b56947fb56000c8dfd50f17eb23c23ac79ea2d254ff3e580d8e9' 
  AND token = 'KM34OTH9tsrM0/zSPm0IpAcDGb6VnFLBpTchKdg1YFw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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