SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5013c6acbfd4df26c1ccbe2f16ffb957ac90bdb82ad0fb049212493699e64a78' 
  AND token = '5MA/358fOlrdAFVLzOthEhjUA3XLINz+1fBFsTBFKdQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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