SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16cdcbb0d3e793f7550dbcfb358b02c19f4f5a068af8ed547a00a23ead465de9' 
  AND token = 'H8k8ICIUSuQaQUxyPv/+FlBsE2obGft5pv8mcP6t/98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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