SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '96b23888dcc4230ac12bd6c7d31fc7e1103ed4ba7c2797523a6482d782c09ed3' 
  AND token = 'SDPYDrR/TRAI3LzuGZ3v+5br0okJgEPBMJGCDU3WCbU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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