SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86e5a5e77b178c52d754507832b0ebee412331950124ddd355092308d93ed7b5' 
  AND token = 'XQnLz5Z3Thf4NWnZgiVsMXJA7jlfIkbl/gUWaqVUptE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}