SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81ac45f32952b506a43984f88a48ec17fc6cbf71d6ea3986eea17ab17ecdc263' 
  AND token = 'f7vlCooESNo/aiSWivjvYKKvm8ljc2sa/l7jIoMDnYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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