SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03d7163f1f8645de7426a607fa93d0f908837fbf0652a85648911702833ea5d7' 
  AND token = 'qQZGYbchuNi5qbo/SoJsthgXFmN/1sAoKzDnG6CdlJs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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