SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f1136c37bcc715aeebb7bf94ddf9854b9da1f91329b4c9a3d82334f448a22a3c' 
  AND token = 'WwZAf94fYSd2asaKAbyW8xvLCsOoKcSCCfgadQ2xJlw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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